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p a 1, 1931- H. M. S HO RT AUTOMATIC CUT-OFF SWITCK Filed Jan. 12, 1928HM Short ATTORN EY WITNESS:

Patented Sept. 1, 1931 UNITED STATES HENRY M. SHORT, OF PENN YAN, NEWYORK AUTOMATIC CUT OFF SWITCH Application filed January 12, 1928. SerialNo. 246,354.

This invention relates to electrical control devices for use inconnection with electric circuits and has for its object the provisionof a novel cut-off switch device adapted to be interposed in an ignitioncircuit or the like and acting to cut-ofi' the flow of current or breakthe circuit upon excessive decrease of pressure in the lubricatingsystem of the engine, motor, or other power device in connection withwhich the device is used, the advantage being that the power device willcease to operate, danger of burning out any bearings thereof on accountof failure of lubrication being avoided.

The invention is particularly well adapted for use in connection withinternal combustion engines having a forced feed lubricating systemalthough it is not intended that there be any particular limitations asto the employment of the device for this particular purpose as it willbe readily appreciated that it may be employed in conjunction with anykind of power device having a forced feed supply of lubricant.

Another object of the invention is to provide a cut-off device of thischaracter which is both thermostatically and pressure operated, the twoactions being complementary.

An additional object is to provide a de- Vice of this character whichwill be simple and inexpensive to manufacture, easy to install, positivein action, eflicient and durable in service, and a general improvementin the art.

With the above and other objects and advantages in view, the inventionpreferably consists in the arrangement and combination of parts to behereinafter more fully described and claimed,'and illustrated in theaccompanying drawing which is a diagrammatic view of the device showingitin association with a lubricant conducting pipe.

Referring more particularly to the drawing the numeral 10 designates aportion of a pipe forming part of a forced feed lubrication system, and11 designates a source of current for an ignition circuit or the like.In carrying out the invention I provide a cut-off switch devicecomprising a substantially U-shaped tubular member 12, having one end incommunication with the pipe 10 as for instance by being embedded withina suitable packing member 13 mounted within an out-standing nipple 14 onthe pipe 10. The other end of the tubular member 12 is closed andcarries a contact 15 located near but spaced from a contact 16 which isfixedly mounted in any desired manner and upon any suitable supportingmeans. The invention further contemplates the provision of a U-shapedthermostatic member 17 which has one arm fixedly mounted at 18 and whichhas its other arm free and carrying a contact 19 adapted to engage thecontact 16 at certain times. 'ound upon the thermostatic member 17 is acoil 20 which is connected by a conductor 21 with one terminal of thesource of current 11 and which is also connected by a conductor 22 withthe free end of the. thermostatic member and electrically with thecontact 15. I

The operation of the device is as follows: The relation of the tubularmember 12 and thermostatic member 17 is such that when no current isflowing through the circuit the contact 15 is out of engagement with thecontact 16 whereas the contact 19 is in engagement with the contact 16as shown in the drawing. Assuming that the device is used in series withthe ignition system of an automobile it is apparent that when theoperator closes the circuit as by the starter switch and starts themotor (both of which are not shown), current will flow from the source11 through the coil 20, conductor 22, free end of the thermostaticmember 17, contact 19, contact 16. and conductor 23 connected with thecontact 16 to and through the ignition system. After the motor has beenin operation for a few minutes the heating effect of the coil 20 willoperate to distort the thermostatic device 17 so that the free endthereof carrying the contact 19 will move toward the stationary end 18,thereby disengaging the contact 19 from the contact 16. This would ofcourse break the ignition circuit, but the timing of the device is soformed that by the time that this occurs the pressure of the lubricantpassing through the pipe 10 has caused the tubular member 12 to expandso Uzi) circulation of oil, have been made.

that the contact 15 carried by the free end thereof will be inengagement with the contact 16 so that the circuit will be completedthrough the contacts 15 and 16 notwithstanding the disengagement of thecontacts 16 and 19. If at any time pressure in the pipe or conduit 10drops below normal the pressure within the tubular member 12 will becorrespondingly reduced and the free end thereof will move toward thestationary end, bringing the contact 15 out of engagement with thecontact 16 and breaking the ignition circuit so that the motor willcease to operate until the oil supply is replenished or until therepairs, necessary to proper supply and It is consequently apparent thatby means of this device burning out the bearings of a motor on-acoountof insufficient lubrication will be entirely avoided. It is believedthat the construction, operation and advantages will be readily apparentto one skilled in the art without further explanation.

As shown in the figure of the drawing, the

conductor wire 23 is in circuit with a movable element 24 of acommutator and with the primary 25 of the coil of the usual ignitionsystem commonly employed in connection with automobile engines, thesecondary Winding of this coil being indicated by the numeral 26, and aspark plug in circuit therewith by the numeral 27, and acondenser 28 isinterposed between the terminal of the primary coil 25 which isconnected with the contact element 24 and the other terminal of the saidprimary winding.

Having thus described the invention I claim In a circuit controllingswitch of the class described, the combination with a conductor for afluid under pressure. an electro-thermostatic unit comprising a U-shapedcore and a winding about the core, connected at one end with one end ofthe core, a contact in circuit with the said end of the winding andcarried by the corresponding end of the core, a fixed contact injuxtaposition to the first mentioned contact and normally engagedthereby, a U-shaped tube connected at one end with the fluid conductorand closed at its other end, a contact upon the last mentioned end ofthe tube in juxtaposition to and nor mally spaced from the fixedcontact,-a conductor wire connecting the last mentioned contact and thecontact upon the core of the electro-thermostatic unit, and conductorsleading from the fixed contact and, from the other terminal of theelectro-thermostatic unit.

In testimony whereof I aflix my signature.

HENRY M. SHORT.

